We have searched for elevated basal plasma somatostatin in patients with documented cholelithiasis (n = 37) and compared the data with healthy control subjects (n = 27). Using an acidic assay system for measuring somatostatin in unprocessed plasma, we could not find deviations from normal values in biliary stone patients. Also basal blood levels of other islet cell hormones (insulin, glucagon) and minerals (calcium, magnesium) are unchanged. Further studies are needed to find out whether an abnormal response of plasma somatostatin to appropriate stimuli can play a role in the etiology of biliary stones.